20437715645 has 4 divisors (see below), whose sum is σ = 24525258780. Its totient is φ = 16350172512.

The previous prime is 20437715633. The next prime is 20437715651. The reversal of 20437715645 is 54651773402.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54651773402 = 2 ⋅27325886701.

It can be written as a sum of positive squares in 2 ways, for example, as 15492531961 + 4945183684 = 124469^2 + 70322^2 .

It is a cyclic number.

It is not a de Polignac number, because 20437715645 - 2¹² = 20437711549 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20437715596 and 20437715605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2043771560 + ... + 2043771569.

It is an arithmetic number, because the mean of its divisors is an integer number (6131314695).

Almost surely, 2^20437715645 is an apocalyptic number.

It is an amenable number.

20437715645 is a deficient number, since it is larger than the sum of its proper divisors (4087543135).

20437715645 is an equidigital number, since it uses as much as digits as its factorization.

20437715645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4087543134.

The product of its (nonzero) digits is 705600, while the sum is 44.

It can be divided in two parts, 204377 and 15645, that added together give a palindrome (220022).

The spelling of 20437715645 in words is "twenty billion, four hundred thirty-seven million, seven hundred fifteen thousand, six hundred forty-five".